Colorectal cancer is one of the most common malignant tumors of the world; it is the second most frequent cause of malignant tumor related mortality in developed countries. In developed countries, mortality rate caused by colorectal cancer seems have a progressively descending tendency in the past 20 years. There are motivations for early diagnosis and for improvement in methods of therapy and medicines. In Taiwan, the rate of suffering for colorectal cancer is rising constantly, furthermore, there is evidence of an age-descending tendency.
According to a 2002 survey by the Department of Health (DOH), the highest level of the executive branch in Taiwan, on the top ten related cancer of Taiwanese population, colorectal cancer (CRC) is the third leading cause of cancer-related death for male and female. About 6681 new cases of colorectal cancer were diagnosed according to statistical data by DOH in 1999, and 3649 patients died in Taiwan due to colorectal cancer according to statistical data by DOH in 2002. The average age of colorectal cancer patient is lower than other countries. In other words, twenty-year-old or thirty-year-old people suffer from the colorectal cancer in Taiwan. Therefore, we can't ignore the possibility of the colorectal cancer occurring in younger populations.
Although methods of diagnosis and surgical operation treatment have improved for colorectal cancer patients, when one makes a comparison between early diagnosis with later period diagnosis by surgical operation, treatment is able to probably overcome colorectal cancer in early diagnosis, but is not able to absolutely overcome colorectal cancer in later period diagnosis. Thus far metastasis are the main problem in the treatment for the colorectal cancer, therefore, a method with high sensitivity, high specificity and easy diagnosis that can detect arly and potentially curable CRC would be a novel target for CRC diagnosis and therapy.
The present invention is to provide functional genetic method, for diagnostic genes of colorectal cancer consist of 71 types of genes, that can be applied for early diagnosing possibility of recurrence and metastasis for colorectal patients. Simultaneously, tracing of 100 colorectal cancer cases have found a 92% genes variation in colorectal tissue. In the process of tracing 100 colorectal cancer cases simultaneously, mutation of genes is found in 92% colorectal cancer tissues. In the tracing process, although CEA of 16 patients remained in normal value range, the method can detect early tumor cells in blood by using genes variation testing.
In WO0055351, ROSEN CRAIG A et. al., entitled “Human Colon Cancer Associated Gene Sequences And Polypeptides”, disclose colon cancer related polynucleotides and the polypeptides encoded by the polynucleotides herein collectively known as “colon cancer antigens”, screening methods for identifying agonists and antagonists of colon cancer antigens of the invention. But, the present invention is to provide SSH and cDNA microarray technology to identify candidate marker genes which are overexpressed continuously from colorectal proliferous polypus to colorectal oncogene, detecting overexpressed genes are selected from up regulation genes which related intently in colorectal cancer oncogene, and down regulation genes which related in colorectal cancer oncogene. The total 71 genes are used to diagnosing early colorectal cancer.